Optical navigation systems detect relative movements between the optical navigation systems and target surfaces to perform tracking operations. An optical navigation system uses a light source, such as a light-emitting diode or a laser diode, and an image sensor to successively capture image frames of a target surface. The optical navigation system compares the successive image frames and estimates the relative movements between the optical navigation system and the target surface based on the comparison between the current image frame and a previous image frame. The optical navigation system is able to track the relative movements between the optical navigation system and the target surface by continuously capturing and comparing image frames.
Optical navigation systems are commonly used in optical computer mice to track the movements of the mice relative to the surfaces on which the mice are manually manipulated. An optical computer mouse can either be corded or cordless. Since a cordless optical mouse operates on a battery, the power consumption of the optical navigation system in the optical mouse is an important consideration. There are a number of conventional techniques to reduce the power consumption of optical navigation systems.
Most conventional techniques to reduce the power consumption of an optical navigation system involve switching the optical navigation system to a sleep mode to save power when the optical mouse is not being used, i.e., when the optical mouse (and the optical navigation system) is not in motion. However, using these techniques, no power saving is achieved when the optical mouse is in motion.
There are conventional techniques that can reduce the power consumption of an optical navigation system even when the optical mouse is in motion by, for example, decreasing the rate at which the image frames are captured. Since the process of capturing an image frame equates to a certain power usage, decreasing the frame rate of the optical navigation system can reduce the power consumption of the optical navigation system. However, these power reducing techniques tend to significantly compromise the tracking performance of the optical navigation system.
In view of these concerns, what is needed is an optical navigation system and method for reducing the power consumption of the system even when in motion without significantly compromising the tracking performance of the system.